Flood warnings issued ahead of Sydney downpour

Sydneysiders are being urged to keep off the roads and prepare for flash flooding as an intense low pressure system bears down upon the coast.

A severe weather warning has been issued by the Bureau of Meteorology for damaging winds and heavy rain in the Sydney and Illawarra Districts, including the adjacent ranges, and coastal areas up to Seal Rocks.

Latest forecasts predict that almost double the monthly average of rainfall for November - or up to 150mm in parts - is expected to fall in 24 hours, exceeding the monthly average rainfall for November.

Simon Lewis, New South Wales Severe Weather manager for the Bureau of Meteorology, said despite the intensity of the system residents can expect it to pass fairly quickly.

“It will cross the coast somewhere between Sydney and Wollongong tomorrow and then move fairly rapidly offshore,” said Mr Lewis.

“One good thing about this system is that it does move through fairly quickly and so we’re not expecting a very long duration of heavy rain, but we are expecting to see quite intense falls sometime tomorrow morning and persist through until tomorrow afternoon.”

More than a month's worth of rain is likely to cause flooding along central parts of the NSW coast during the middle of this week. (Weatherzone)Heavy rain is expected to lash NSW. (AAP)

Related

Lewis said coastal residents should prepare for some of the side effects of a deep low pressure system such as damaging southerly winds and huge surf.

“We’re also expecting quite strong winds to develop – that’s most likely to start up in the afternoon when the low starts to move offshore,” said Mr Lewis.

“We’ll see fairly damaging wind gusts across a wide stretch of the New South Wales coast”

“Once the low starts to move away tomorrow, we also expect those strong winds to whip up quite hazardous surf conditions.”

A state-wide hazardous surf warning has also been issued for NSW ahead of the rainfall, with the BoM saying conditions in the water could become dangerous along the entire coastline.

Damaging winds averaging up to 70 km/h with gusts in excess of 90 km/h are expected to buffet the entire coast from Illawarra up to the Central Coast.

Some areas could see more than a months' rain. (AAP)

NSW Police have also taken the unusual step of warning road users to avoid driving unless necessary as flash flooding is expected to dramatically reduce breaking distance.

“With severe rain predicted tomorrow after what has been warm weather roads will become slippery and unpredictable,” said Chief Inspector Phillip Brooks from the Traffic and Highway Patrol Command.

“We’re asking all road users to perhaps consider the need to be on the roads throughout what will be a severe rain event tomorrow.

“Tomorrow’s weather will be particularly dangerous for motorcycle riders and cyclists and if they are on our roads they should wear bright coloured clothing, be seen by other vehicles and share the road safely.”

The State Emergency Service has advised residents to move their vehicles under cover and away from trees and to secure loose items around their houses and yards.

Around 3000 volunteers are on standby for when the wild weather hits, preparing for a spike in rescue calls.

The last time Sydney was hit by such a large east coast low pressure system, the NSW SES performed 150 rescues and authorities are expecting more than that to be required tomorrow.